advise please

[savage sausage]

I'm currently porting my cylinder on my 98 250 and have bought some gaskets for the top end rebuild, Im looking to get more mid -top end power.

whats he deal with the base gaskets do I need more or less ??

any ideas or help would be appreciated
thanks

 

[Jakobi]

I'm currently porting my cylinder on my 98 250 and have bought some gaskets for the top end rebuild, Im looking to get more mid -top end power.

whats he deal with the base gaskets do I need more or less ??

any ideas or help would be appreciated
thanks

Can't really say to be honest. When you say porting do you mean you've made ports bigger? moved them slightly? or just cleaned up some rough casting?

If its the later and you want mid-top performance you will want to have the exhaust port flush with the top of the piston at bottom dead center. You might need one gasket, or more.. It will depend on the bike and its manufacturing tolerances. Mine took a 1.3mm stack to achieve this.

If you've gone about reshaping ports etc then its anyones guess.

 

[gasgasman]

If the porting is done right, you will need the same gasket used to make the port height measurements.

 

[Jakobi]

If the porting is done right, you will need the same gasket used to make the port height measurements.

Correct! The person doing the porting should have taken the deck height into consideration prior to starting work.

 

[savage sausage]

Can't really say to be honest. When you say porting do you mean you've made ports bigger? moved them slightly? or just cleaned up some rough casting?

If its the later and you want mid-top performance you will want to have the exhaust port flush with the top of the piston at bottom dead center. You might need one gasket, or more.. It will depend on the bike and its manufacturing tolerances. Mine took a 1.3mm stack to achieve this.

If you've gone about reshaping ports etc then its anyones guess.

I've reshaped the transfer ports & boost port to match the base gasket,and removed all the cast flashing and smoothed them same with the exhaust port.

but I haven't altered the exhaust port and transfer port window height or width.

Ok thanks for the heads up on the exhaust port flush on BDC